Phonograph attachment



Sept. 23, 1924. I 1,509,540.

T. H. CAMPBELL PHQNOGRAPH ATTACHMENT Filed June 20. 1922 llt'VZ/EEOR W.

A TTORNE Y3 li atented Sept. 23, 1924.

PATENT OFFICE.

THOMAS H. CAMPBELL, 0F TEMPLE, TEXAS.

PHONOGRAPH ATTACHMENT.

Application filed June 20, 1922.

To all whom it may concern:

Be it known that I, THOMAS H. CAMPBELL,

to provide a simple and serviceable tone modifier for a phonograph whereby the tones produced are softened or modified.

In the preferred form of my invention the tone modifier is formed of a block preferably of metal. fine or more grooves are formed in the block, which; grooves are adapted to fit over and engage the needle bar of an ordinary reproducer or sound box. lflach groove in the tone modifier block is of irregular shape, preferably curved, so that when the groove is fitted over the needle bar the latter will be slightly deflected and the tone modifier will be frictionally held thereon.

in the drawings, illustrating a preferred form of the invention and forming part of this specification vFig. 1 is a front elevation of a sound box or reproducer having a tone modifier applied to the needle bar.

l1 ig. 2 is a side elevation of the parts shown in Fig. 1, a part being broken away to show the diaphragm and adjacent end of the needle bar.

Fig. 3 is a perspective view of a tone modifier showing somewhat diagrammatr eally a fragment of a needle bar in place.

in said drawings, 5 indicates the body portion of a conventional type of reproducer or sound box, and 6 indicates the usual diaphragm therein. The sound box or reproducer is provided with a needle bar 7 which is pivoted at 8 to a lug 9 on the sound box. One end of the needle bar carries the needle 10 while the opposite end is secured to the diaphragm 6 at 11. The

Serial No. 569,687.

needle bars of sound boxes of the present type are relatively thin as indicated particularly in Fig. 1.

in order to soften or modify the tone produced in the phonograph I have provided novel means for attachment to the needle bar for varying the vibrations therein and thus modifying the tones produced. In the specific form shown the tone modifier is in the form of a block 12 preferably formed of metal such as brass, though the specific material of which the tone modifier is made is not in all cases material. In the block I have indicated three grooves 13, 14, 15 and these grooves are preferably are shaped or curved so as to be of irregular shape. These grooves are of varying widths to accommodate needle bars of varying thicknesses on sound boxes of different types or make. While the grooves shown are all in one face of the rectangular block it should be understood that this arrangement is not necessary for the grooves might be otherwise disposed.

When it is desired to modify the tone produced in the sound box the tone modifier is applied to the needle bar preferably by placing the end of the groove of the proper size over the needle bar adjacent its inner end and then sliding the block along the needle bar toward the periphery of the sound box. If the grooves are of irregular shape the needle bar will be slightly deflected and the tone modifier will be frictionally held thereon. Due to the modification of the effective vibrating portions of the needle bar when the tone modifier is adjusted, the tones produced will be materially modified and softened.

ll hile I have illustrated and described a preferred form of my invention, 1 wish it understood that various modifications and changes may be made within the scope of the appended claim.

I claim:

As an article of manufacture, a tone modifier to be applied to the needle bar of a phonograph sound boX comprising a block of substantially rigid material having a groove therein of tortuous form.

THOMAS H. CAMPBELL. 

